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NOAA Updates its Global Surface Temperature Dataset

New version has complete global coverage

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Providing reliable and quality climate information allows government agencies, researchers, and others to make informed decisions that can save lives and improve quality of life. Since the late 1990s, NCEI has provided a suite of climate services, including the monthly Global Climate Report, to support this mission. One of its most highly visible and widely used products is NOAA’s global surface temperature dataset (also known as NOAAGlobalTemp), which is an authoritative dataset used to assess observed global climate change. 

NOAAGlobalTemp has been used by multiple science organizations such as the World Meteorological Organization and in assessments, such as the Intergovernmental Panel on Climate Change and the Bulletin of the American Meteorological Society (BAMS) State of the Climate reports. It is also usually compared to other respected global surface temperature datasets such as those produced by NASA and the UK Met Office, among others.

Through the years, the main data sources for the NOAAGlobalTemp dataset have been the Global Historical Climatology Network - Monthly (GHCNm), which uses weather stations across the land surfaces, as well as the Extended Reconstructed Sea Surface Temperature (ERSST), which uses ships, buoys, surface drifters, profiling floats, and recently other uncrewed automatic systems, over the ocean surfaces. This allowed for great global coverage; however, the polar regions were excluded in previous versions. 

As technology improves and additional data sources become available, it is essential to update these datasets in order to provide the most accurate depiction of the Earth’s environmental conditions—updated datasets help support informed decision-making, as well as educating the public on climate change. 

NCEI will switch to an updated version of NOAAGlobalTemp on February 14, 2023, with the release of the January 2023 Global Climate Report. This new version includes complete global coverage. The two main improvements include improved scientific methods for infilling areas with little to no data as well as the addition of air temperature data in the Arctic Ocean from the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) and the International Arctic Buoy Program (IABP) to improve spatial coverage, especially across the Arctic. The second improvement is that the data record now begins with January 1850, extending the record back in time an additional 30 years.

The Arctic is the fastest-warming region in the world, warming at least three times faster than any other region on Earth. The exclusion of this region in previous versions of NOAAGlobalTemp resulted in a very slight cold bias in the global average, particularly in recent years.

The new version of NOAAGlobalTemp corrects this and, while ranks and anomalies may change slightly, the main conclusions regarding global climate change are very similar to the previous version:

  • Global trends over decadal and longer time scales are consistent.
  • The top-10 warmest years on record have occurred since 2010 and the last nine years (2014-2022) are the nine-warmest years on record.

However, the new version shows significantly more warming in the Arctic since 1980, which is mainly a result from complete coverage in the polar region.